Igniter



E. H. HAUGEN Nov. 5, 1957 IGNITER Original Filed Oct. 25, 1951 INYE'NTOR EDMOND H. HAUGEN ATM WNEYS United States Patent Oflice 2,812,016 Patented Nov. 5, 1957 IGNITER Edmond H. Haugen, Oakmont, Pa., assignor to Scaife Company, Oakmont, Pa., a corporation of Pennsyl- Vania Continuation of application Serial No. 253,033, )ctober 25, 1951. This application April 2, 1956, Serial No. 575,382

6 Claims. (Cl. 15828) This invention relates to rotary wall flame type fluid fuel burners and especially to the ignition system thereof, and this application is a continuation of application Serial No. 253,033 which is now abandoned.

Within burners of this type, fluid fuel droplets are projected or sprayed by a rotating fuel head against a metal flame rim at the periphery of the combustion chamber where, after vaporization and admixing with air, the mixture is ignited and burns above the flame rim. This ignition is usually accomplished by an electric spark jumping a gap between the conductive metal flame rim serving as one electrode and a suitable metal electrode which is electrically insulated from, but located adjacent, the flame rim. One or more spark gaps may be provided in a burner as desired.

The level of the trajectory of the oil droplets with respect to the location and length of the spark gap is an important factor in obtaining efficient combustion. With some proposed igniters adjustment is difficult because the adjustable electrode is located well within the combustion chamber which has only a relatively small access door, and the adjustments are located below the hearth. Others involve expensive adjustment structures.

In the past, one practice has been to fix the electrode permanently in a predetermined location, but manufacturing tolerances and errors and also the fact that different heating conditions require different electrode positions has prevented maximum efliciency of performance, so that provision for adjustment is desired as a practical matter.

The insulated electrode must be carefully located with respect to the flame rim to set the optimum spark gap. Constructions for attempting to properly position the spark gap have been used and two are disclosed in United States Patents to Wilson et al., No. 2,220,858 and Wilson No. 2,522,552. In those patented burners, the actual spark gap distance is determined by rotative adjustment of the insulated electrode with respect to the flame rim, and the vertical location of the spark gap relative to the oil trajectory level is determined by vertical adjustment of the insulated electrode. Installation workers have found in prior burners that these separate adjustments were difficult to correlate, especially when a worker tried to hold the rotative adjustment while setting the vertical adjustment of the electrode. The present invention is an improvement over these constructions.

It is therefore the major object of this invention to provide a novel structure for accurately and speedily setting the ignition spark gap in a rotary wall flame oil burner.

A further object of this invention is to combine the spark gap and vertical electrode adjustments into a single operation.

Another object of this invention is to provide a novel inexpensive ignition electrode holder and insulator for oil burners or the like.

A further object of the invention is to provide a novel oil burner electrode assembly wherein a special internally threaded bushing is fixed to the lower end of a porcelain holder.

These and other objects will become apparent as the specification proceeds in connection with the appended claims and the annexed drawings wherein:

Figure l is a fragmentary elevational view partially in section of an oil burner embodying the ignition system of the present invention;

Figure 2 is a fragmentary enlarged section view showing details of the electrode stem bushing; and

Figure 3 is a top plan view of the electrode assembly illustrating the position of the electrode relative to the flame rim.

The specification proceeds with continued reference to the drawings wherein like reference characters designate the same parts throughout the several views.

Referring to Figure l, the burner includes a combustion chamber that is partitioned from a lower chamber 11 by a hearth 12 of suitable refractory material mounted upon a metal hearth pan 13 which is peripherally supported by lugs 14 of surrounding side wall 15.

Within the lower chamber 11, an electrically driven burner unit 16 is suspended from hearth 12 and hearth pan 13 in a conventional manner as by stud bolts 17. Burner unit 16 comprises a motor 18 and a rotor having oil flinger tubes 19 and a fan 20 extending through and above the hearth.

An annular flame rim 21 having a vertical fuel impingement wall 22 and an air deflecting wall 23 is mounted on hearth 12 surrounding the burner unit, and suitable flame holders or grilles 24 are mounted atop wall 22.

A circular opening 25 is formed in hearth 12 adjacent the flame rim and its lower end is surrounded by a surface recess in which is seated an annular metal plate 26 imbedded or otherwise rigid with hearth 12. Hearth pan 13 is apertured in alignment at 27. The ignition unit :8 passes through these apertures as will be described in etai Ignition unit 28 comprises a rigid holder or body 29 of porcelain or like electrically insulating refractory material having a cylindrical portion 31 within aperture 25 and a reduced tapered lower portion 32. Holder 29 is formed intermediate its ends with a smooth central bore 33 which slidably and rotatably receives the cylindrical vertical shank 34 of a metal electrode rod 35. Above guide bore 33, holder 29 is formed with an enlarged cylindrical bore 36 providing an upwardly open cup. An integral boss 37 surrounds the rod and projects into the bottom of the cup so as to provide an annular basin 38 at the bottom of the cup below the point where rod 35 merges from bore 33.

The conical portion 32 of holder 29 is formed below guide bore 33 with an enlarged cylindrical bore 39 surrounded at its open lower end by a further enlarged annular surface recess 41.

An electrode stem bushing 42 is mounted in the lower end of holder 29. This bushing is of metal, preferably stainless steel or brass so as not to corrode in service, and comprises an externally threaded, knurled, corrugated or other surface roughened portion 43 within bore 39, an enlarged annular flange 44 seated in recess 41 and a boss 45 having an internally threaded bore 46 projecting below holder 29. In some embodiments of the invention recess 41 is not provided and flange 44 merely abuts against the flat lower end of the holder 29 in the assembly. The pitch of the threads at 46 is preferably small so that an entire turn of rod 35 will move the rod only a very small distance vertically.

The diameter of externally threaded portion 43 is approximately that of bore 39, and at the factory the space between threads 47 and the bore 39, the space about bushing neck 48 and the walls of recess 41 are supplied with a suitable ceramic cement 50 which is hardened to anchor the bushing 42 permanently to holder 29, with threaded bore 46 axially in alignment with smooth bore 33.

The cylindrical rod shank 34 is threaded at its lower end at 49 to be rotatably threaded in bore 46 and project downwardly therefrom. A lock washer 51 surrounds the rod between a nut 52 on threaded rod section 49 and the flat end 53 of bushing 42. A nut 54 on threaded rod section 49 clamps the metal terminal strip 55 to rod 35.

Above boss 37 rod 35 has secured thereto. a flange 56, the purpose of which will appear, and its upper end is bent over at 57 to terminate in a sharpened tip 58 near wall 22 For supporting holder body 29 in the assembly, a rigid metal ring 59 is axially fixed within opening 25 as by welding it to a metal strap. 61 which extends from a portion 62 underlying and in electrical contact with the flame rim down opening 25 and there beyond to provide a second electrical terminal strip at 63. Ring 59, which is supported by strap 61, underlies radial flange 64 on the top of body 29 to support the latter with its upper end level with the hearth. A split metal band 65, having its ends secured, by a screw assembly 66, surrounds body 29 below opening 25. Collar 65 is rigidly supported by an integral angular extension 67 fixed as by welding to plate 26. Collar 65 is fixed to strap 611 by a screw assembly indicated at 68. When screw 66 is tightened band 65 is tightened about the body 29 to prevent its movement relative to the hearth.

A workman, in the process of installation, reaches into the combustion chamber and rotates the electrode rod which is threaded in bushing 42 until the tip 58 is located at the optimum height with respect to the flame rim. He then rotates the rod through whatever fraction of a single turn may be necessary to attain the predetermined spark gap distances. Although this further rotation slightly changes the height adjustment, the thread pitch at 46 is so small that the change has no appreciable effect on operation.

The workman then reaches into chamber 11 below hearth l2 and places lock washer 51 and nut 52- on the threaded end 49 of the electrode rod. When nut 52 is tightened this locks the settings of tip 58 which he had made in the combustion chamber 10. He then places spring terminal clip 55 and nut 54 on the threaded end of the electrode rod and tightens nut 54 to lock the terminal clip to the rod.

Ignition performance during operation of a burner is related to the oil impingement level at the flame rim. A service man may prefer to change the igniter tip height rather than the oil impingement level, and this is readily done in the structure of the invention.

In operation, motor 18 rotates the oil flinger tubes and the fan to project oil and air against the metal flame rim where the oil is vaporized as it impinges against wall 22 and admixed with air flow into and to the sides of the combustion chamber 10. The mixture is ignited when starting the burner by a spark across the spark gap from the electrode rod tip 58 to the flame rim wall 22 Later the hot flame rim and the burning mixture maintain the flame.

During starting, when the burner is running cold, some oil impinges against the upper section of shank 34 of the electrode rod and flows down the shank to flange 56 which extends to as great if not a greater diameter than the top of the boss 37. The descending oil then runs out of the edge of flange 56 and drips intobasin 38 where it eventually evaporates as the burner temperatures rise. The flange 56 also serves to limit the height adjustment range of the electrode rod.

If any oil should get past flange 56 and flow down shank 34 of the electrode rod into and along the bore 33 and into the bushing 42, the long threaded engagement of the locked rod and bushing at 46 provides an oil tight seal which prevents seepage of oil into chamber 11. There can be no leakage of oil between the exterior of bushing 42 and holder body 29 because the bushing is permanently cemented and sealed in place.

The foregoing disclosure describes a new and improved oil burner igniter which is of simple inexpensive construction and is easier to install and adjust than known igniters.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In an oil burner assembly, a hearth having an aperture, an electrical igniter mounted in said aperture comprising a rigid body of electrical insulating material secured in said aperture, said body having an upwardly open recess, a downwardly open recess and vertical bore of smaller size connecting said recesses, a metal bushing rigidly anchored in fluid tight assembly in said downwardly open recess and having an internally threaded bore coaxial with said vertical bore, a metal electrode rod having an upper spark tip portion projecting from the top of said body so as to be located above said hearth in the burner, a vertical shank freely guided in said vertical bore and an end portion threaded in said bushing bore so as to be rotatable therein for vertical and spark gap distance adjustment of said spark tip portion, the pitch of the coacting threads of said rod and bushing being such that a complete turn of the rod moves the rod only a very small distance vertically to that after said rod has been rotated in said bushing until the correct height of said spark tip is attained any further rotation of the rod through a part of a turn to obtain the desired spark gap distance does not operatively change the height adjustment, and means on said threaded rod portion below said bushing for securing said rod to said bushing for locking said adjustment.

2. In an oil burner assembly, a hearth having an aperture, an electrical igniter mounted in said aperture comprising a rigid body of electrical insulating material secured in said aperture, said body having an upwardly open recess, a downwardly open recess and an intermediate vertical bore of smaller size connecting said upwardly and downwardly open recesses, ametal bushing having a roughened exterior cemented into said downwardly open recess so as to be permanently secured to said body and prevent leakage of oil between said bushing and downwardly open recess wall, said bushing having an internally threaded bore coaxial with said intermediate bore, a metal electrode rod having an upper spark tip portion projecting from the top of said body so as to be located above said hearth in said burner, a. vertical. shank guided in said intermediate bore and an end portion threaded in said bushing so as to be rotatable therein for universal adjustment of said spark tip portion, the pitch of the coacting threads of said rod and bushing being such that a. complete turn of the rod moves the rod only a very small distance vertically so that. after said rod has been rotated in said bushing until the correct height of said spark tip is attained. any. further rotation of the rod through a part of a turn to obtain the desired spark gap distance does not operatively change the height adjustment, and threaded fastener means on said threaded rod. portion below the bushing coasting with said bushing for locking said adjustment.

3. In an oil burner assembly, a hearth having an aperture, an electrical igniter mounted in said aperture comprising a rigid body of electrical insulating material secured in said aperture, said body having an upwardly open recess, a downwardly open recess and an intermediate vertical bore of smaller size connecting said upwardly and downwardly open recesses, a metal bushing rigidly anchored in said downwardly open recess and having an internally threaded bore coaxial with said intermediate bore, said downwardly facing recess having an enlarged shoulder at its lower end and an enlarged radial flange being provided on said bushing for seating against said shoulder, means sealing against leakage of oil between the bushing and said body, a metal electrode rod having an upper spark tip portion projecting from the top of said body so as to be located above said hearth in said burner, a vertical shank guided in said intermediate bore and an end portion threaded in said bushing so as to be rotatable therein for adjustment of said spark tip portion, the pitch of the coacting threads of said rod and bushing being such such that a complete turn of the rod moves the rod only a very small distance vertically so that after said rod has been rotated in said bushing until the correct height of said spark tip is attained any further rotation of the rod through a part of a turn to obtain the desired spark gap distance does not operatively change the height adjustment, and means on said threaded rod portion coacting with said bushing below said body for locking said adjustment.

4. In an oil burner assembly, a hearth having an aperture, an electrical igniter mounted in said aperture comprising a rigid body of electrical insulating material sccured Within said aperture, said body having in vertical alignment an upwardly open recess, a downwardly open recess and an intermediate vertical bore of smaller size connecting said upwardly and downwardly open recesses, a metal bushing having a roughened external surface cemented in oil tight assembly with said body in said downwardly open recess and having an internally threaded bore coaxial with said intermediate bore, a metal electrode rod having an upper spark tip portion projecting from the top of said body so as to be located above the hearth in said burner, a vertical shank guided in said intermediate bore and an end portion threaded in said bushing so as to be rotatable therein for vertical and lateral adjustment of said spark tip portion, the pitch of the coacting threads of said rod and bushing being such that a complete turn of the rod moves the rod only a very small distance vertically so that after said rod has been rotated in said bushing until the correct height of said spark tip is attained any further rotation of the rod through a part of a turnto obtain the desired spark gap distance does not operatively change the height adjustment, and means on said threaded rod portion coacting with said bushing for locking said adjustment.

5. For use in assembly with an oil burner of the type wherein fluid fuel droplets are projected or sprayed across a hearth and wherein ignition of the fuel is accomplished by an electrical spark jumping a gap between a metal flame rim on said hearth and an electrical igniter positioned in an aperture in said hearth, an improved construction for said electrical igniter comprising a rigid body of electrical insulating material adapted to be secured in said aperture, said body having an upwardly open recess, a downwardly open recess and a vertical bore of smaller size connecting said recesses, a metal bushing rigidly anchored in fluid tight assembly in said downwardly open recess and having an internally threaded bore coaxial with said vertical bore, a metal electrode rod having an upper spark tip portion projecting from the top of said body so as to be located above the hearth in the burner in said assembly, a vertical shank freely guided in said vertical bore and an end portion threaded in said bushing bore so as to be rotatably therein for vertical and spark gap distance adjustment of said spark tip portion in said assembly, the pitch of the coacting threads of said rod and bushing being such that a complete turn of the rod moves the rod only a very small distance vertically so that after said rod has been rotated in said bushing until the correct height of said spark tip is attained in said assembly any further rotation of the rod through a part of a turn to obtain the desired spark gap distance does not operatively change the height adjustment. and means on said threaded rod portion below said bushing for securing said rod to said bushing for locking said adjustment.

6. For use in assembly with an oil burner of the type wherein fluid fuel droplets are projected or sprayed across a hearth and wherein ignition of the fuel is accomplished by an electrical spark jumping a gap between a metal flame rim on said hearth and an adjacent electrical igniter positioned in an aperture in said hearth, an improved construction for said electrical igniter comprising a rigid body of electrical insulating material adapted to be secured within said aperture and extend below the hearth, said body having an upwardly open recess, a. downwardly open recess and a vertical bore of smaller size connecting said recesses. a metal bushing rigidly anchored in fluid tight assembly in said downwardly open recess and having an internally threaded bore coaxial with said vertical bore, a metal electrode rod projecting upwardly from the top of said body and having an angularly disposed spark tip portion adapted to extend over the hearth so as to be located above the hearth in the burner in said assembly, said rod having a vertical shank freely intermediately guided in said vertical bore and an end portion threaded in said bushing bore so as to be rotatable therein for vertical and spark gap distance adjustment of said spark tip portion with respect to said flame rim in said assembly, the pitch of the coacting threads of said rod and bushing being sufficiently fine that a complete turn of the rod moves the rod only a very small distance vertically so that after said rod has been rotated in said bushing until the correct height of said spark tip is attained in said assembly any further rotation of the rod through the part of a turn necessary to obtain the desired spark gap distance does not operatively change the height adjustment, and means on said threaded rod portion below said bushing for securing said rod to said bushing for locking said adjustment.

References Cited in the file of this patent UNITED STATES PATENTS l,40l,585 Collins Dec. 27, 1921 1,612,091 Bernal Dec. 28, 1926 2,354,223 Smith et al July 25, 1944 2,396,306 Van Haase Mar. 12, 1946 2,522,552 Wilson Sept. 19, 1950 2,545,945 Ensign Mar. 20, 1951 2,552,550 Haugen May 15, 1951 

